1. Field of the Invention
The present invention relates to a cooling system of a power semiconductor module, and particularly to a cooling system of a power semiconductor module in which a desirable temperature environment is realized and maintained by controlling the cooling capacity of a cooling fluid.
2.Description of the Related Art
Conventionally, in inverter devices using power semiconductors, there are many examples in which water-cooled or liquid-cooled cooling systems are applied for cooling.
In a related technique, a temperature sensor is fixed to a plate of a part to be cooled, and a control is perform such that the temperature of the plate is detected, and monitoring is performed as to whether the temperature exceeds a predetermined temperature, and in a case where the temperature of the plate exceeds the predetermined temperature, power supply is automatically cut off (see, for example, patent document 1).
[Patent document 1] Japanese Patent No. 2581367
As control means for the case where the detection temperature of the temperature sensor exceeds the predetermined temperature, in the case where the power supply is cut off, for example, in the case where a motor as a load of an electric vehicle or a hybrid vehicle is controlled, the behavior of the vehicle is rapidly changed, and there occurs a state which is not desirable for the driver.
Besides, there is known that in a heat exchange part where cooling is actually performed, the state of flow of cooling water has a great influence on a heat transfer coefficient.